Organizations use more and more social tools for their day to day information sharing. They can use well established products like Twitter or Facebook, but also internal tools to conserve authority on their properties. The use of these tools gives a new knowledge source for the organization, through the status messages, links between collaborators: this is what we call "social fragments". The organizations begin to realize that they lose a part of their knowledge by not capitalizing social fragments. Actual knowledge management tools are not able to correctly handle these social fragments and their value is lost for the organizations. It appears to be the next challenge in knowledge management to correctly handle these two types of fragments: the social and more classical documentary fragments. We purpose a semantic way to answer this problem, by modeling and developing a knowledge management system, which could interact with both fragments: the Social Organization Content Management System (SOCMS). The SOCMS approach is based on an ontology built in the Heudiasyc lab at the Université de Technologie de Compiègne and on several other web semantic standards. The use of these standards allows the organization to branch its own system to other knowledge source from all over the web. In this article we present and justify this model and the prototype of a collaborative platform which use it.